DHCP client on VLAN interface



  • Hi there,

    I've struggled with this problem for a while now and am really out of ideas.

    I want to run pfSense "on a stick", where LAN and WAN interfaces are all VLAN interfaces on a single physical port, which connects as trunk to a switch (whether this is a good idea or not is a different topic).

    The managed switch then "splits" that trunk out to different access ports for the different LANs (going to wireless access points, all of which works just fine and as intended) as well as the WAN. The WAN access port connects to a Netgear Cable modem (which is in "bridge mode").

    The problem is that pfSense just won't get a DHCP address on the WAN interface from my provider. I can see the DHCP Requests being sent out, and from what I can see they are leaving the switch ok, but I never get a response. Of course, the ISP won't help me with this "non standard" config. At the same time, packet dumps on pfSense WAN interface reveal lots of chatter coming in from the cable connection (arp requests, as well as other DHCP messages [for other customers around me]).

    So I'm pretty confident the switch is set up correctly, what with trunk and access ports, permitted VLANs, etc.

    So wondering - are there maybe any general known issues with pfSense's DHCP client running on a VLAN interface? Or do you have any other ideas what could be going wrong?

    Thanks for any pointers…............... !

    PS: If I connect the pfSense machine directly to the modem, without any tagging etc, I can get a DHCP address from my provider just fine.


  • LAYER 8 Netgate

    Is this maybe the ISP getting the MAC address of the switch because of spanning-tree or something?

    Try disabling spanning-tree on the switch port going to the cable modem.


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